Morphological characterization of seeds and germination efficiency of Pinus patula var. longepedunculata and P. pseudostrobus var. oaxacana

Abstract

Pinus patula and P.pseudostrobus are species of great economic importance for different communities in the Oaxaca State due tothe wood quality and wide use in forest commercial plantations and reforestation. The objective of this research was to evaluate themorphological variation of seeds and their germination efficiency of two pine species under greenhouse conditions. In 2022,selected seeds of outstanding phenotypes was obtained from the Instituto Nacional de Investigaciones Forestales, Agrícolas yPecuarias (INIFAP); three seed samples of 10 g per species were made, the number of seeds was counted, and the equatorial (DE)and polar (DP) diameters and shape coefficient (CF=DE/DP) were measured; sowing was carried out in 49 cavity trays with amixture of mountain forest soil, vermiculite®, agrolite® and Peat Moss® with a 4:1:1:2 ratio. Germination was counted daily andvigor indicators were determined: germinative energy (EG), energy period (PE), germinative speed (VG) and germination speedindex (IVG). Data were analyzed using t-Student tests and regression analysis (α=0.05) in the SAS program. Including days aftersowing (DDS) in the model, we found that between 78 and 84 % of the existing variation in the percentage of accumulatedgermination was explained in both species. P.pseudostrobus presented more spherical (CF=0.41) and heavier seeds (24.27 mg)with an energy period of 69 % at 22 DDS; on the other hand, P.patula has elongated (CF=0.31) and light seeds (8.20 mg) with agreater energy period of 83% at 20 DDS. Both species germinate after 15 days; however, P.patula has a higher germination rateand a higher germination percentage, it is necessary to use germplasm from outstanding phenotypes to guarantee the reproductiveefficiency of the seed and subsequent seedling quality.